Exploring the Angular Size-Redshift Relation in Cosmology

In summary, the angular size-redshift relation is a promising way to test cosmological ideas, but is hindered by technical difficulties at very high redshifts. Observations have shown inconsistent results with the predicted behavior, leading to a lack of data to support the CDM model's predictions for objects with z>1.5. However, this issue is often ignored in forums that favor the standard view.
  • #1
TrickyDicky
3,507
27
The angular size-redshift relation has always looked like an interesting way to test cosmological ideas since the L-CDM model predicts this apparently strange behaviour for redshifts higher than around z=1.6, but sadly is plagued with technical difficulties arisin mainly from these very high redshifts. I recently read something (Gurvits 1998) but it's quite dated and it was rather inconclusive with several observations outside the values predicted by the L-CDM model. Perhaps someone knows about more recent observations the shed light about this issue. Thanks.
 
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  • #2
The lack of observational data in accordance with the predicted increase in angular size for objects with z>1.5 is one of the many weak points of the CDM model but you won't find much information about it in this forum since they tend to ignore anything that doesn't support the standard view.
 

Related to Exploring the Angular Size-Redshift Relation in Cosmology

1. What is the Angular size-redshift relation?

The Angular size-redshift relation is a relationship between the angular size of an object in the sky and its redshift. It states that as the redshift of an object increases, its angular size decreases.

2. How does the Angular size-redshift relation relate to the expansion of the universe?

The Angular size-redshift relation is a result of the expansion of the universe. As the universe expands, the light from distant objects gets stretched, causing their wavelengths to increase and their redshift to increase as well. This leads to a decrease in their angular size.

3. Can the Angular size-redshift relation be used to measure the expansion rate of the universe?

Yes, the Angular size-redshift relation can be used to measure the expansion rate of the universe. By measuring the redshift and angular size of a large sample of objects, scientists can determine the rate at which the universe is expanding.

4. Are there any limitations to using the Angular size-redshift relation?

There are some limitations to using the Angular size-redshift relation. It assumes that the objects being studied are at the same distance from Earth, and it also relies on accurate measurements of redshift and angular size. Additionally, the relation may be affected by other factors such as the intrinsic size of the object and gravitational lensing.

5. How does the Angular size-redshift relation support the Big Bang theory?

The Angular size-redshift relation is consistent with the predictions of the Big Bang theory. It supports the idea that the universe is expanding and that the further away an object is, the faster it is moving away from us. This is reflected in the relationship between redshift and angular size, as objects with higher redshifts are farther away and therefore appear smaller in the sky.

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